useful adj. 1.有用的,有益的,有效的,有幫助的。 2.〔俚語〕值得稱贊的,精通…的 (at)。 make oneself generally useful 事事有用,事事幫得來忙 (He must make himself generally useful. 他可事事都干得來)。 a pretty useful performance 相當(dāng)精采的演出。 His wife is very useful at cooking. 他的妻子很會(huì)做菜。 adv. -ly ,-ness n.
Unlike pilots which are used for estimation of channel and must waste some useful bandwidth , the ppss , whose power can be boosted 3db or 6db to suppress efficiently the additive noise , is useful data transmitted , thus efficiency of the ofdm has been increased 與用于做信道估計(jì)的導(dǎo)頻符號(hào)不同, ppss傳輸?shù)氖怯杏玫臄?shù)據(jù),因此提高了系統(tǒng)的帶寬利用率, ppss的平均功率增加3db或6db可有效抑制信道的加性高斯噪聲。